net/mlx4_en: Verify coalescing parameters are in range

Add check of coalescing parameters received through ethtool are within
range of values supported by the HW.
Driver gets the coalescing rx/tx-usecs and rx/tx-frames as set by the
users through ethtool. The ethtool support up to 32 bit value for each.
However, mlx4 modify cq limits the coalescing time parameter and
coalescing frames parameters to 16 bits.
Return out of range error if user tries to set these parameters to
higher values.
Change type of sample-interval and adaptive_rx_coal parameters in mlx4
driver to u32 as the ethtool holds them as u32 and these parameters are
not limited due to mlx4 HW.

Fixes: c27a02cd94d6 ('mlx4_en: Add driver for Mellanox ConnectX 10GbE NIC')
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/en_ethtool.c

@@ -1027,6 +1027,22 @@ static int mlx4_en_set_coalesce(struct net_device *dev,
 	if (!coal->tx_max_coalesced_frames_irq)
 		return -EINVAL;
 
+	if (coal->tx_coalesce_usecs > MLX4_EN_MAX_COAL_TIME ||
+	    coal->rx_coalesce_usecs > MLX4_EN_MAX_COAL_TIME ||
+	    coal->rx_coalesce_usecs_low > MLX4_EN_MAX_COAL_TIME ||
+	    coal->rx_coalesce_usecs_high > MLX4_EN_MAX_COAL_TIME) {
+		netdev_info(dev, "%s: maximum coalesce time supported is %d usecs\n",
+			    __func__, MLX4_EN_MAX_COAL_TIME);
+		return -ERANGE;
+	}
+
+	if (coal->tx_max_coalesced_frames > MLX4_EN_MAX_COAL_PKTS ||
+	    coal->rx_max_coalesced_frames > MLX4_EN_MAX_COAL_PKTS) {
+		netdev_info(dev, "%s: maximum coalesced frames supported is %d\n",
+			    __func__, MLX4_EN_MAX_COAL_PKTS);
+		return -ERANGE;
+	}
+
 	priv->rx_frames = (coal->rx_max_coalesced_frames ==
 			   MLX4_EN_AUTO_CONF) ?
 				MLX4_EN_RX_COAL_TARGET :

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

@@ -132,6 +132,9 @@
 #define MLX4_EN_TX_COAL_PKTS	16
 #define MLX4_EN_TX_COAL_TIME	0x10
 
+#define MLX4_EN_MAX_COAL_PKTS	U16_MAX
+#define MLX4_EN_MAX_COAL_TIME	U16_MAX
+
 #define MLX4_EN_RX_RATE_LOW		400000
 #define MLX4_EN_RX_COAL_TIME_LOW	0
 #define MLX4_EN_RX_RATE_HIGH		450000
@@ -552,8 +555,8 @@ struct mlx4_en_priv {
 	u16 rx_usecs_low;
 	u32 pkt_rate_high;
 	u16 rx_usecs_high;
-	u16 sample_interval;
-	u16 adaptive_rx_coal;
+	u32 sample_interval;
+	u32 adaptive_rx_coal;
 	u32 msg_enable;
 	u32 loopback_ok;
 	u32 validate_loopback;